proteins

• amino acid -> peptide -> polypeptide -> protein
• protein is a molecule consisting of polypeptides (polymers of amino acids) folded into 3D shapes
• comprised of Carbon, Hydrogen, Oxygen, Nitrogen, and sometimes Sulfide
• The shape of the protein determines its function
• Proteins are amphiprotic
• Amphiprotic = has characteristics of both base and acid. capable of reacting as either
• Amino Acids are organic molecules which have an amino group and a carboxyl group.
• Amino acid structure. Amino is NH3, it is on the left. A hydrogen is attached to the center (C) on top. Carboxyl is CO2, with a double bond on one of the O, it is on the right side of the carbon. Below the carbon is a R, meaning that it can be anything

  
• Polar = hydrophilic
• nonpolar = hydrophobic
• charged/ionic = hydrophilic
• hydrophilic means that it is attracted to water and polar molecules
• hydrophobic means that it is not attracted to water and is repelled by it
• R = side chain
• each amino acid has a unique side chain. the unique aspects of amino acid are based on the side chain's physical and chemical properties. Side chains can be grouped as Nonpolar, Polar, and Charged/Ionic
• Protein Synthesis is the making of polypeptides or an amino acid polymer
• amino acids are joined by PEPTIDE BONDS by a DEHYDRATION synthesis or a CONDENSATION reaction
• a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water.
• polypeptides are many amino acids joined together by peptide bonds
• polypeptides are made in the cytoplasm of cells through protein synthesis
• each polypeptide has a unique sequence of amino acids and formation. One end is a free amino group (N-terminus), and the other end is a free carboxyl group (C-terminus)
• peptide linkage: a bond formed between two peptides that occurs when a dehydration synthesis reaction takes place
• protein shape is determined by the sequence of amino acids in the polypeptide chain
• every protein molecule has an amino end (N terminus) and a carboxyl end (C Terminus)
• Overall shape of protein is determined by the order and chemical behavior of the amino acids
• the protein shape can be changed by temperature
• protein functions as a structural building block (which includes nails and hair), and as a functional molecule. For example, enzymes (a type of protein) act as biological catalysts, ensuring chemical reactions proceed at speeds that sustain life.
• protein has 4 levels of structure: Primary, secondary, tertiary, and quaternary
• The primary structure of a protein is the sequence of amino acids in a polypeptide chain. it is determined by genes and dictates secondary and tertiary forms
• secondary structure is the coiling and folding polypeptide's chain as more amino acids are added during protein synthesis due to hydrogen bonding within the polypeptide backbone
• a helix is a type of polypeptide structure which has tight coil, stabilized by hydrogen bonds C=O, N-H bonds
• beta pleated sheets (looks like a fan) are also stabilized by hydrogen bonds between polypeptide chains lying SIDE BY SIDE
• tertiary structures are the supercoiling (3D folding) of a polypeptide that is stabilized by side-chain interactions
• quaternary structure consists of 2 or more polypeptide chains intertwined forming a functional protein
• in quaternary structures, the polar molecules move outside of the chain because they're hydrophilic, and nonpolar molecules move inside of the chain because they're hydrophobic
• protein sequencing allows scientists to determine the primary structure of proteins and enzymes
• degradation is the breakdown of a substance into simpler substances by chemical reactions